Places queries

[DigDug]

Running into an error writing an extension. Thought maybe someone here
could help. I'm trying to query places for things written into a
textbox. I'm using some options to limit and sort the results though.
The code looks something like:

var query = this.history.getNewQuery();
query.searchTerms = this.textbox.value;

var options = this.history.getNewQueryOptions();
options.sortingMode = options.SORT_BY_VISITCOUNT_DESCENDING;
options.maxResults = 20;

this.result = this.history.executeQuery(query, options);

When I run this the DOMi tells me that the generated query is something
like (guessing at the text because I can't get to it right now):

place:&terms=text&sortmode=8&maxresults=20

however, that search is often empty. If I remove the two options,
generating just

place:&terms=text

a much better result shows up. Is this a bug, or an error in how I'm
writing this?